Comparison of Serum HBsAg Quantitation by Four Immunoassays, and Relationships of HBsAg Level with HBV Replication and HBV Genotypes

BACKGROUND: The decline in hepatitis B virus surface antigen (HBsAg) may be an early predictor of the viral efficacy of Hepatitis B virus (HBV) therapy. The HBsAg levels obtained by different immunoassays now need comparing and the relationships between levels of HBsAg and HBV DNA alongside HBsAg and genotype must be evaluated. METHODOLOGY/PRINCIPAL FINDINGS: HBsAg levels were compared among 80 patients using the Abbott Architect assay, a commercial immunoassay approved for HBsAg detection and quantitation, and three other assays derived from immunoassays approved for HBsAg detection (manufactured by Diasorin, Bio-Rad and Roche). Good correlation was found between the Abbot vs. Diasorin, Bio-Rad and Roche assays with narrow 95% limits of agreement and small mean differences: -0.06 to 0.11, -0.09 log(10) IU/mL; -0.57 to 0.64, -0.04 log(10) IU/mL; -0.09 to 0.45, -0.27 log(10) IU/mL, respectively. These agreements were not affected by genotypes A or D. HBsAg was weakly correlated with HBV DNA, whatever the HBsAg assay used: Abbott, ρ = 0.36 p = 0.001, Diasorin ρ = 0.34, p = 0.002; Bio-Rad ρ = 0.37, p<0.001; or Roche ρ = 0.41, p<0.001. This relationship between levels of HBsAg and HBV DNA seemed to depend on genotypes. Whereas HBsAg (Abbott assay) tended to correlate with HBV DNA for genotype A (ρ = 0.44, p = 0.02), no such correlation was significant for genotypes D (ρ = 0.29, p = 0.15). CONCLUSION/SIGNIFICANCE: The quantitation of HBsAg in routine clinical samples is comparable between the reference assay and the adapted assays with acceptable accuracy limits, low levels of variability and minimum discrepancy. While HBsAg quantitation is not affected by HBV genotype, the observed association between levels of HBsAg and HBV DNA seems genotype dependent

Feedback on the Implementation of a Rapid and Connectable Point-of-Care COVID-19 Antigen Test in an Emergency Department

Faced with the pandemic viral circulation of SARS-CoV-2, healthcare establishments have had to maintain an effective screening strategy in order to prevent nosocomial clusters. Automated antigenic tests appear to be a reliable and complementary alternative to RT-PCR (reverse transcriptase polymerase chain reaction) in order to optimize patient care in the emergency department. We report our experience of the deployment of the LumiraDx antigen tests on the LumiraDx platform, as well as the comparison of these tests’ results with the RT-PCR results on a population of patients sampled in the emergency department

Severe Acute Respiratory Syndrome Coronavirus 2 Nucleocapsid Antigen in Urine of Hospitalized Patients With Coronavirus Disease 2019

International audienceAbstract Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid antigen (N-Ag) can be detected in the blood of patients with coronavirus disease 2019 (COVID-19). We used a highly sensitive and specific assay to explore the presence of N-Ag in urine during the course of COVID-19 and its relationship with the severity of disease. Methods We studied urinary and plasma N-Ag using a highly sensitive immunoassay in 82 patients with SARS-CoV-2 infection proved by polymerase chain reaction. Results In the first and second weeks of COVID-19, hospitalized patients tested positive for urinary N-Ag (81.25% and 71.79%, respectively) and plasma N-Ag (93.75% and 94.87%, respectively). High urinary N-Ag levels were associated with the absence of SARS-CoV-2 nucleocapsid antibodies, admission in intensive care units, high C-reactive protein levels, lymphopenia, eosinopenia, and high lactate dehydrogenase levels. Higher accuracy was observed for urinary N-Ag as a predictor of severe COVID-19 than for plasma N-Ag. Conclusions Our study demonstrates that N-Ag is present in the urine of patients hospitalized in the early phase of COVID-19. As a direct marker of SARS-CoV-2, urinary N-Ag reflects the dissemination of viral compounds in the body. Urinary N-Ag may be a useful marker for disease severity in SARS-CoV-2 infections

RNA testing for the diagnosis of acute hepatitis A during the 2017 outbreak in France

International audienc

Diagnosis value of SARS‐CoV‐2 antigen/antibody combined testing using rapid diagnostic tests at hospital admission

International audienc

Temporal evolution of HBsAg and HBV DNA in five patients with persistente HBV infection.

<p>HBsAg log₁₀ IU/ml (▪ and solid line), HBV DNA (▵ and dotted line).</p

Correlation of HBsAg (log₁₀ IU/mL) and HBV DNA (log₁₀ IU/mL).

<p>(A) VHB genotype A, Abbott <i>ρ</i> = 0.44, p = 0.02; Diasorin <i>ρ</i> = 0.49, p = 0.01; Bio-Rad <i>ρ</i> = 0.46, p = 0.02; Roche <i>ρ</i> = 0.47, p = 0.02; (B) genotype D, Abbott <i>ρ</i> = 0.29, p = 0.15; Diasorin <i>ρ</i> = 0.05, p = 0.81; Bio-Rad <i>ρ</i> = 0.30, p = 0.14; Roche <i>ρ</i> = 0.38, p = 0.05.</p

Plots of Log₁₀ IU/ml HBV-DNA/HBsAg ratio by levels of HBV replication.

<p>Plots of Log₁₀ IU/ml HBV-DNA/HBsAg ratio by levels of HBV replication.</p